What you sell, you no longer own. Yes, you can sell yours, but it is not necessary and you would be better off in almost all cases not doing this.
A pact is not (as @Winters says) the same thing, one may have a pact to work on a project, or a pact for lifelong mentoring, or a pact to sell your soul for eternity, but they do not have to go together and for most of us, they don’t.
My soul is my own, it is the seat of My power.